The son of a New Jersey mayor was accused yesterday of abducting a Staten Island teen at knifepont and taking him on a two-hour terror ride to force the youth to end his online relationship with the man’s 14-year-old daughter.

John Gregorio Jr., 45, the son of Linden Mayor John Gregorio, surrendered to authorities and pleaded not guilty at his arraignment in Staten Island Supreme Court to an indictment charging him with kidnapping, unlawful imprisonment, robbery and menacing in connection with the alleged incident last July.

His daughter and the 14-year-old boy had exchanged phone numbers online, and the teen had called her home in New Jersey, police sources said.

On one occasion, he telephoned her, and after they got into a fight, Gregorio got on the phone and told the teen to stop calling her, sources said.

The boy cursed Gregorio and hung up, police sources said.

Days later, on July 19, at 8:35 p.m., Gregorio and “two others who remain unidentified” forced the teen’s older brother into a car “believing him to be his brother,” the Richmond District Attorney’s office said in a statement.

Gregorio got the teen to contact his brother, and he, too, was allegedly coerced into the car.

Gregorio told the teen not to call his daughter anymore and to leave her alone, police sources said.

“Gregorio is alleged to have threatened both brothers’ lives at knifepoint,” the DA’s statement said.

Gregorio’s lawyer, John Murphy Jr., said in a statement that “the complaining witness in this case does not have clean hands.”

Murphy said his client has “several very young daughters” and that an investigation will show that “these very young girls were preyed upon.”